Marine actinomycete diversity, biogeography, and secondary metabolite production

Actinomycetes are the single most important source of bioactive microbial products yet discovered. Although these bacteria are best known from soils, they can also be recovered from marine samples if the appropriate growth conditions are provided. The goals of this research were to gain a better understanding of marine actinomycete diversity, population genetics, and secondary metabolite production. The results have been interpreted using modern theories of prokaryotic genomics, speciation, and population biology. The research detailed herein is focused on marine actinomycetes belonging to the genus Salinispora as species within this taxon are proving to be model organisms with which to address fundamental questions about actinomycete biology. Chapter I provides an introduction to marine actinomycetes and the context within which the research described in subsequent chapters was performed. Chapter II presents a detailed study of the actinomycete diversity cultured from marine sediments collected around the island of Guam in the South Pacific. Chapter III explores the biogeographical distributions of the actinomycete genus Salinispora. Chapter IV is the result of the surprising discovery that Salinispora species produce secondary metabolites in a predictable, species-specific manner. This chapter includes a description of the patterns observed and the evolutionary implications of this finding. Chapter V provides a summary of the research performed and directions for future research in this fiel